This invention relates to a cloth-like tubular connector for interconnecting adjacent ends of conduits through which particulate or granular material is flowed.
Particulate or granular material, such as rice, wheat and other grains, plastic pellets, sand and the like, frequently are conveyed through tubular conduits wherein one of the conduits is oscillated or vibrated or otherwise moved relative to the other. For example, the particulate material may be flowed from a storage bin through a tubular conduit and into a conduit or conduit-like opening in a sorting machine which is vibrated or oscillated. For this and other types of connections where a flexible connection is necessary between two adjacent open ends of conduits or conduit-like openings, a tubular flexible connector is commonly used. Typically, such connectors are made of elongated tube of a cloth-like material whose upper and lower ends are arranged to overlap the adjacent edge portions of the conduits and are secured thereto by means of an elastic band. An example of such a type connector is disclosed in U.S. Pat. No. 3,516,694 issued June 23, 1970 to Schwartz.
In the prior connector tubes, such as illustrated in the foregoing prior patent, the upper and lower ends of the cloth-like tube are hemmed to form a channel within which an elastic band is positioned for elastically or resiliently gripping against the respective overlapped conduit portions. In addition, a stiffer, but resilient band, such as one made of a coil spring configuration is arranged around the middle of the tube and is secured thereto for maintaining the shape of the tube.
Because such connectors are typically used in conveying relatively abrasive granular material the cloth wears out rapidly and the tubes must be replaced periodically. Attempts to prolong the lives of these tubes have generally involved using heavier fabrics, laminations of different kinds of fabrics, stiffer fabrics, etc. While these different innovations, such as the use of laminations of different fabrics have substantially prolonged the lives of these tubes, nevertheless, their lives are relatively short.
In addition, many kinds of granular material include fine dust-like particles which tend to work their way through the spaces in the woven cloth-like material utilized for this purpose. In some applications, the dust can be severe enough to require measures for clearing the air around the connector.
Next, particulate material tends to flow in a liquid-like manner through the connector and, consequently, creates a venturi effect. That is, the flow of the fluid-like material causes a reduction the the pressure in the interior of the tube. Thus the tube tends to collapse inwardly to some degree. The amount of inward flexing or collapse varies with different interior pressures that are caused by variation in flow rates, types of materials, etc. The inward flexing of the tube adversely effects the seal between the tube ends and the overlapped conduit ends and also, increases wear.
This invention is concerned with improving a flexible connector tube to reduce the wear, dust, seal and other problems associated with prior connector tubes.